1. Field of the Invention
The invention relates to a device for introducing binary data into a medium by means of n.gtoreq.4 parallel available channels of said medium, comprising a coding device having a data input and a number of separate data outputs which are parallel-wise connected to relevant separate inputs of data channels among said n channels of the medium in order to apply, synchronously with the supply of one data to each of said data channels as a first group, at least one error correction bit, formed from a second group of data bits intended for said data channels, to an error correction channel among said channels of the medium. The medium may be a magnetizable material which is driven along a read/write head device. In that case, introduction is to be understood to mean storage. Alternatively, a number of channels for data transmission may be concerned. In that case, introduction is to be understood to mean transmission.
2. Description of the Prior Art
A device of the described kind is known from U.S. Pat. No. 3,697,947. The known technique concerns three data channels and one error correction channel and is based on a convolution code. The formation of the error correction bits is realized by means of EXCLUSIVE-OR logic or modulo-2 addition. An arbitrary error in a group of, for example, three parallel data bits can be corrected by the convolution code used. Obviously, such mutilated three-bit characters must be spaced sufficiently apart. The invention, however, is based on the recognition of the fact that errors are usually limited to a single data channel in which the errors can occur in a closely spaced (but unknown) series. The known code does not offer a solution in this respect. Furthermore, a character-organized error correction would required a large amount of redundancy.